1. Field of the Invention
The present invention relates generally to manufacture and use of mTOR inhibitors for oral administration in the prevention and treatment of medical maladies in humans and other animals. More particularly, the invention relates to manufacture and use of preparations for oral administration that include an mTOR inhibitor together with polymers and stabilizers for prevention and treatment of medical maladies, most especially in the fields of oncology, neurology, and healthy lifespan extension in humans and other animals.
2. Description of Related Art
Rapamycin (also known as sirolimus) is a well-known pharmaceutical agent that has long been used to minimize organ transplant rejection. Rapamycin and its analogs and derivatives famously act to inhibit its namesake metabolic pathway—the mammalian target of rapamycin (“mTOR”). The critical metabolic roles of the mTOR pathway have long led to broad speculation about possible medical uses for rapamycin outside of organ transplant rejection. However, despite the success with prevention of transplant rejection, and despite the many long-felt needs and corresponding tremendous efforts in developing rapamycins for other indications, effective use of rapamycin for treating or preventing other disorders has not been widely successful and has been very limited at best. The likely reasons why it has not been widely used outside of preventing organ transplant rejection are varied and speculative, ranging from its raw chemistry to poor compliance and scary side effects (rumored to include high mortality rates largely due to dosing in early trials from the 1960s or 1970s).
For additional technical descriptions and a detailed description of the related art, this application incorporates by reference the entirety of US Patent Application 2012/0064143 A1, Inhibition of Mammalian Target of Rapamycin, which has original priority dating to Nov. 11, 2008.
Particular formulations taught in US Patent Application 2012/0064143 (the “2008 Discoveries”) provided particles or “cores” containing the active rapamycin ingredient, and those cores were microencapsulated within a polymer matrix, for oral administration of the rapamycin. The rapamycin cores were microencapsulated using a spinning disk atomization coating process with a polymer matrix known under the “Eudragit S-100” name. The Eudragit S-100 polymer matrix includes a particular methacrylate polymer that is generally stable at pH levels below 7 and was used to protect the rapamycin from degrading in the acidic conditions of the stomach. Then, once the microencapsulated rapamycin entered basic conditions (i.e., pH greater than 7) within the intestines, the matrix would dissolve and, theoretically, the undegraded rapamycin would be absorbed through the intestinal walls and become bioavailable for its intended medical purposes.
Unfortunately, theory and practice do not always match perfectly. Despite tremendous hope for broad efficacy of the orally administered use of such microencapsulated rapamycin preparations, and despite widespread national and international attention to the 2008 Discoveries, significant concerns remained about whether sufficiently predictable and effective levels of rapamycin could be reliably delivered to the body in this form. For reasons that long remained uncertain in practice, stability of the basic rapamycin molecule within such formulations has been less reliable than desired, and uncertainties have mounted with respect to whether enteric absorption levels can be reliable enough for adequate market acceptance of the 2008 Discoveries. Consequently, there is a need for improved encapsulated rapamycin preparations—preparations that still capitalize on the 2008 discoveries but that improve various performance characteristics, such as storage stability, biodistribution, dosage cost, etc.
In addition, because the potential applications are so wide and varied and yet relatively unproven for an oral form of rapamycin, that wide variety itself presents an impediment to realizing publically available use of such a preparation. Given the market dynamics and regulatory requirements of pharmaceutical industries, a successful effort to actually make embodiments of the 2008 Discoveries available for use by the public would require much more than minimizing uncertainties about the preparation itself. A successful effort to do so must identify and validate a particular, highly-impactful indication for which the benefits of using a microencapsulated rapamycin would be relatively irrefutable, and the effort must likewise develop corresponding methods and strategies for effectively and reliably addressing as much.